So called “solid ink” printers encompass various imaging devices, including printers and multi-function platforms and offer many advantages over many other types of high speed or high output document reproduction technologies such as laser and aqueous inkjet approaches. These often include higher document throughput (i.e., the number of documents reproduced over a unit of time), fewer mechanical components needed in the actual image transfer process, fewer consumables to replace, sharper images, as well as being more environmentally friendly (far less packaging waste).
A schematic diagram for a typical solid ink imaging device is illustrated in FIG. 1. The solid ink imaging device, hereafter simply referred to as a printer 100 has an ink loader 110 which receives and stages ink sticks which remain in solid form at room temperatures. The ink stock can be refilled by a user by simply adding more ink as needed to the ink loader 110. Separate loader channels are used for the different colors. For, example, only black ink is needed for monochrome printing, while ink colors of black, cyan, yellow and magenta are typically needed for color printing. Each color is loaded and fed in independent channels of the ink loader.
An ink melt unit 120 melts the ink by raising the temperature of the ink sufficiently above its melting point. During a melting phase of operation, the leading end of an ink stick contacts a melt plate or heated surface of the melt unit and the ink is melted in that region. The liquefied ink is supplied to a single or group of print heads 130 by gravity, pump action, or both. In accordance with the image to be reproduced, and under the control of a printer controller (not shown), a rotating print drum 140 receives ink droplets representing the image pixels to be transferred to paper or other media 170 from a sheet feeder 160. To facilitate the image transfer process, a pressure roller 150 presses the media 170 against the print drum 140, whereby the ink is transferred from the print drum to the media. The temperature of the ink can be carefully regulated so that the ink fully solidifies just after the image transfer.
While there may be advantages to the use of solid ink printers compared to other image reproduction technologies, high speed and voluminous printing sometimes creates problems not satisfactorily addressed by the prior art solid ink printing architectures. To meet the large ink volume requirement, ink loaders must have large storage capacity and be able to be replenished by loading ink at any time the loader has capacity for additional ink. The ink sticks may likewise be much larger.
In typical prior art solid ink loaders, the ink sticks are positioned end to end in a linear channel or chute with a melt device on one end and a spring biased push block on the other end. This configuration requires the operator to manually advance the ink in the chute to provide space to insert additional ink sticks, to the extent there is capacity in the channel. This configuration may be somewhat cumbersome for loading large quantities of larger ink sticks in newer, larger capacity and faster printing products, as the operator has to repeatedly insert an ink stick and then push it forward manually when loading multiple ink sticks in the same channel.
A loader for a solid ink delivery system should accept the proper ink stick and reject of not permit the entry of an improper ink stick. If the ink stick is too large, it is somewhat simple to prohibit its entry into the chute of the ink delivery system. However, when the ink stick that is improper is smaller than the proper ink stick it becomes more difficult to ensure that the smaller improper ink stick is not inserted into the chute and advanced to the melting unit. Further, for high-capacity, high-volume solid ink printing, the use of large ink sticks is preferred. The use of large ink sticks results in smaller improper ink sticks more easily being placed within the chutes of the ink delivery systems. The system disclosed herein is directed to alleviate some of the aforementioned problems.